Flagpole Truck – OT Series For external halyard poles — Cap Style — Single Pulley Cast aluminum construction with cast nylon pulley (1- 7/16″ outside diameter on OTH, OT1 and OT25; 2″ outside diameter on OT2, OT3, OT325 and OT35) on 1/4″ stainless steel axle. Designed to slip over the top of the flagpole and be secured by stainless steel set screws (one 1/4″-20NC on the OTH; three 5/16″-18NC on the OT1, OT2, OT25, OT3, OT325 and OT35). The top of the truck is designed to accept an ornament with a spindle threading of 1/2″-13NC as standard but can be supplied with other sizes of threading if desired. The ornament is secured to the truck with a size 10-32 stainless steel pan head screw. The recommended maximum halyard diameter is 5/16″.